Dr Mourik said the Board's directive was vital because doctors "are the worst judges of our own ability".

"You think you're still as good as you used to be, and we know that that's not true.

"Your cognitive knowledge is reduced, your eyesight is reduced.

"Your time operating becomes longer and longer, and yet you still think you're terrific."

In 1973, when Dr Mourik was a registrar at an English hospital, he was horrified to see a senior surgeon's hands shaking during an operation.

"But he felt he was at the peak of his ability. We knew that wasn't true.

"During a hysterectomy we often had to stop the patient bleeding - we took over the operation - because his eyesight wasn't good and his hands were shaky, his ego was massive. He was a danger to the community.

"It was an issue then and it's an issue now."

Although there are exceptions, he knew a Victorian doctor in his 80s whose practice rightly stopped employing him. "He was an accident waiting to happen."

"You need someone to sit with you, ask you some questions, see how up to date you are.

"A lot of these people don't bother opening their medical journals, they don't go to conferences.

"They're way behind the eight ball. Their practice is out of date, their drug prescriptions are out of date, their knowledge is out of date and they need to be monitored by a strong authority and that's what the medical board is."

Health checks were not disrespecting ageing doctors.

"It's actually a bonus to people if they do get assessed and find out that they're practising perfectly safely."